When human epidermal growth factor 2 (HER2) is amplified or overexpressed, as is the case for about 20% of gastric cancers and 6% of colorectal cancers, there is an increased activation of cellular proliferation and differentiation pathways, tumor progression, metastasis, and resistance to treatment, which substantially affects the prognosis of patients with these cancers [2–4]. Here, ERBB2 is linked to colorectal cancer.